Metal bending brake with rear-wardly slidable clamping beam



Jan. 1%, 1950 R. WEBB 2,494,149

- METAL BENDING BRAKE WITH REARWARDLY SLIDABLE CLAMPING BEAM Filed July26, 1947 2 Sheets-Sheet l INVENTOR. 05,527 1. (2)258.

BY J M his I 1 TTOE/VE XS.

Jan. 30, 195G R. L'. WEBB 2,494,149

METAL BENDING BRAKE WITH REARWARDLY SLIDABLE CLAMPING BEAM Filed July26, 1947 2 Sheets-Sheet 2 INVENTOR. 26 Passer L. 62/255.

-BY Li 5 5. fiwww fi m Patented Jan. 10, 1950 Q .F El CE METAL BENDINGBRAKEWITHREAR- WARDLY SLIDABLE CLAMPING BEAM Robert L. Webb, Imperial,Pa. 7 Application July 26, 1947, Serial No.'763,815

This invention relates to metal bending machines and, in particular, tosheet metal bending brakes.

Such brakes customarily include a bedplate to which is pivoted a'met'albending beam and on which rests a metal clampin beam, and the bend ismade clamping the metal between the clamping beam and the bedplate andswinging the bending beam up against the clamping beam. Usually, theclamping beam is provided with a beveled front or working edge to permitbends greater than 90 and, in metal clamping position, this edge isclosely aligned with the front edge of the bedplate and the working edgeof the bending beam. One disadvantageof prior brakes is that their bendseither are not'as sharp as desired or the'bencling deforms the metal.This is due to the fact, since no adequate provision is made for the thckness of the metal being bent, when the bending beam presses the metalagainst the aligned working edge of the clamping beam, either one or theother of these members must give a distance equal to the gauge of themetal, or the metal itself will be pinched and possibly torn. Attemptshave been made to overcome this which, generally, provide means, such asa setscrew or the like, by which the position of the clamping beam canbe adjusted manually so as to place the working edge of that beam backfrom the bending beam a distance equal to the gauge cf'the metal beingbent. "This is unsatisfactory since time-taking manual adjustments mustbe made for each dif- 3 Claims. Cl. 153- 16) ter'ent gauge of metal andalsc'because it is i difficult to make accurate manual adjustments.Further, the use of such adjusting mechanism results in undesirablyrounded bends since, during the initial swing of thebending beam, thereis no surface abuttin the metal and, consequently no initial sharpcrease is formed in the metal.

It is therefore an object of this invention to provide a metalben'dingbrake in which, during the bendin operation, the clamping beamautomatically adjusts itself to the proper position for making sharpbends;

A more specific object is to provide a brake in which the clamping beamis so mounted that during the metal clamping operation, its working edgemoves automatically into alignment with the front of the bedplate, and,during the metal bending operation; gradually retreats from such alignedposition a distance equal to the gauge of the metal. I

-A further object is to provide such a brake with mechanism for clampingthe metal, which exerts a forward pressure on the clamping beam andevenly'distributes the clamping pressure throughout the clampin beambefore and during the bending operatic g According to the invention, aspacing member or'bloclr is provided which spaces the rear portion ofthe brakes clamping beamfrom the "bedplate so that the beam is rockablymounted thereon. Thebeam is provided in the usual man- -ner with a frontbeveled edge which, when the beam is rocked to clamping position,engages and clamps the metal which is inserted between it and thebe'dpl-ate. The rocking motion is imparted to the beam by metal clampingmechanism which, when tightened, exerts pressure on the beam, thismechanism being mounted at each end of the clamping beam in alignedholes and openings provided in the bedplate and the clamping beamrespectively. The openings in the clamping beam are made larger thanthat portion of the clamping mechanism received therein so that the beamis free to tilt in the openings and permit the rocking motion, and thebeam is sized so that, when rocked, its beveled front "edge swings intoexact alignment with the front edge of the bedplate. Further, theopenings are so formed that when the bending beam is swung upwardly tobend the metal the clamping beam is free to move rearwardly in theopenings at least a distance equal to the gauge of the metal. Inoperation, the increasing pressure of th metal being bent graduallyforces the clamping beam to retreat so that no unnecessary strains areset 'up in the metal and the bends will be as sharp as possible.

The preferred embodiment of the invention is illustrated in theaccompanying drawings "of which Fig. 1 is a perspective view of a brake'e'mploying the invention; Figs. 2 and 3 are sections along the linesIIII and 'I'II-III, respectiv ely, of Fig. 1; Figs. 4 and 5 are viewssimilar to Fig. 3 showing other metal bending positions; "and Figs. 6,"7 and '8 are enlargements of Figs. 3, =4 and 5, respectively,illustrating the rocking and sliding movements of the clamping beam.

Referring to the drawings, the brake illustrated in Fig. 1 isconstructed for the most part like that described and claimed in mycopending application Serial Number 724,809, filed January 23, 1947,which includes a bedplate I and clamping beam 2 between which is clampeda metal "sheet '3, and a bending beam It is pivct'allyswun'g t'othebedplate by means of hinges 6. .In opmeans of cam mechanism 'i' whichbears against the bedplate, and the bend made by swinging the bendingbeam upwardly against the clamping beam by means of handles 8 attachedat its ends. In order to provide the brake with sufficient rigidity andstrength to bend the gauges of metal normally used, the bedplate andclamping beam each are reinforced by angles 9 and II, and the bendingbeam is formed of an angle. This construction provides an unusuallylight and strong brake which can be easily carried to the location ofthe job, and in addition, a brake which is capable of performing thework exceptionally fast due principally to the speed with which the cammechanism can be operated to clamp or release the metal.

. particular machine is capable of bending.

One feature of the invention is the fact that clamping beam 2 is movablymounted with 'respect to the bedplate in such a manner that the beamautomatically positions itself before and during the bending, in thebest position for making sharp bends in the metal. To accomplish this,instead of allowing the clamping beamto rest flush, in the usual manner,against the bedplate, spacing blocks hi are disposed between thesemembers at their rear port-ions sothatthe clamping beam rests in atilted position with only its front edge 46 contacting the bedplate,this front edge being beveled back and being the working edge aroundwhich the metal is bent. Preferably, two square spacing blocks M areemployed. one at each end of the clamping beam, and the blocks areintegrally formed on or welded to the beam. but it should be noted thatit would also be ossible to use concave spacers and secure them eitherto the clamping beam or the bedplate.

As previously stated. cam mechanism is used to press the clamping beaminto metal clamping position. and, when operated. it acts to rock theclamping beam on spacing blocks l4 and arcuately swing beveled edge l5of the beam into clamping position. When the metal is clamped it is heldbetween the bedplate and front beveled edge l6 of the beam and. as shownin Figs. 2 and 3, when the cams are released, coil springs l9, mountedbetween the beam and plate, lift the beam clear of the plate. Althoughthe preferred cam mechanism is the same as that previously described inthe copending application above referred to, it nevertheless isparticularly well adapted for use with the improvements of thisinvention and to obtain these improvements it is mounted in a specialmanner. The mechanism, which is provided at either end of the clampingbeam, includes a cam 2| into which is threaded a cam handle 22, and thecam bears against a pair of cam discs 23 and 24 which in turn bearagainst a cam plate 25 resting on the clamping beam. Cam 2!, as shown inFig. 2, has a pair of bifurcated cam arms between which a setscrew 21 ismounted on a pivot pin 28, the setscrew extending downwardly throughaligned openings 3!, 32 and 33, provided in the cam discs. cam plate andclamping beam respectively,

and being tightly secured in the bedplate in a threaded hole 3 3 whichis positioned in axial the clamping beam and also permits a horizontalmovement of the beam during bending. Generally, these motions arepermitted by making the diameter of the aligned openings 3|, 32 and ofFigs. 6, '7 and 8 will most clearly explain the reasons for thisparticular mounting of the clamping beam. Referring to Fig. 3, theclamping beam is shown in a raised position to permit the insertion ofmetal and, in this position, spacing block I4 rests flush against thebedplate and its rear wall is in vertical alignment with the rear wallsof the beam and bedplate. In the enlargement of Fig. 6, it is seen thatthe cam setscrew extends through aligned openings 3!, 32 and 33 in sucha manner that it engages only the lower bottom surface of each openingand the top front surfaces of each opening are spaced forwardly of thesetscrew a distance preferably equal to the gauge of the metal beingbent.

In the next step, illustrated in Figs. 4 and 7, the metal has beenclamped by swinging cam handle 22 backward to exert pressure on theclamping beam and rock it forwardly on spacing block l4 into a positionin which its front beveled edge is in exact alignment with the frontedge of the bedplate, this position being desirable so that the metalwill begin to crease around the beam during the first part of thebending. By referring to Fig. 7, it will be seen that, in the clampedposition. the beam has tilted about the setscrew so as to bring the axesof the openings into alignment with the setscrew and the rear surfacesof the openings and setscrew into full contact with each other. Also, inthis position the front surfaces of the openings are spaced forwardly ofthe setscrew an amount equal to the differences in diameters of thescrew and openings, and this amount represents the gauge of the metalbeing bent.

In the final bending step illustrated in Figs. 5 and 8. bending beam 6has been swung upwardly through from its normal position. Durin thebending, the thickness of the metal has exerted increasing lateralrearward pressure on the clamping beam until the beam has been finallymoved to the full extent permitted by the differences in diameters ofthe openings and the setscrew. This fact is apparent from the positionof the setscrew with respect to the openings shown in Fig. 8, and alsofrom the fact that, as shown in Fig. 5, the rear end wall of the beamhas been forced out over the rear wall of the bedplate. As the beam isforced rearwardly against the forward pressure of the earns the normalfriction which would be present is reduced due to the fact that it isriding only on the forward edge of the spacing block. Another apparentbut important function occurring during this movement of the clampingbeam is that the beam is pushed by the metal directly in front of theinitial crease so that the final bend is made around the initial creaseand un- 33 larger than the portions of the setscrew which 5 usuallysharp bends result. After the bend has been completed, the cam mechanismis released, the clamping beam automatically returning to its Fig. 3position by the extension of the lifting coil springs 19.

One further feature of the invention, which should now be readilyunderstandable, lies in the use of the particular cam mechanismdescribed. Thus, when the mechanism is tightened against the rockablebeam it exerts a forward as well as a downward pressure, so that thepressure exerted by the metal as it is bent must overcome this forwardpressure with the result that the backward movement of the beam isgradual and not sudden as might be the case with other clamping devices.Further, the lower face of upper disc 23 is convex while the upper faceof the lower disc is concave so that the clamping pressure is evenlydistributed. Such matching spherical radii discs are well known but areof particular value in maintaining even pressure distribution during thebeams rocking and lateral movement.

According to the provisions of the patent statutes, I have explained theprinciple and construction of my invention and have illustrated anddescribed what I now consider to represent its best embodiment. However,I desire to have it understood that, within the scope of the appendedclaims, the invention may be practiced otherwise than as specificallyillustrated and described.

I claim:

1. A sheet metal bending brake comprising a bedplate provided at itsends with holes, a clamping beam having a beveled front edge andopenings aligned with said bedplate holes, a spacing member disposedbetween the rear portions of said plate and beam, a bending beampivotally secured to said bedplate, clamping beam lifting means forraising said beveled front edge clear of said plate to permit theinsertion of metal therebetween, and metal clamping cam mechanismreceived in said aligned holes and openings, said mechanism beingloosely mounted in said clamping beam openings and said openings beinglarger than the portion of the cam mechanism received therein and havingtheir axes inclined rearwardly of the vertical so as to permit saidclamping beam to rock forwardly and position its beveled edge in exactaligmnent with the forward edge of the bedplate when said cam mechanismis tightened and also to permit the beam to slide rearwardly when saidmetal is being bent at least a distance equal to the gauge of saidmetal, whereby a sharp bend is formed in said metal.

2. A sheet metal bending brake comprising a bedplate provided at itsends with holes, a clamping beam having a beveled front edge andopenings aligned with said bedplate holes, a spacing member disposedbetween the rear portions of said plate and beam, a bending beampivotally secured to said bedplate, clamping beam lifting means forraising said beveled front edge clear of said plate to permit theinsertion of metal therebetween, and cam clamping mechanism received insaid aligned holes and openings, said mechanism including a setscrewsecured in said bedplate hole, a cam associated with said setscrew and acam plate disposed between said cam and clamping beam, said plate havingan opening aligned with each of said clamping beam openings and saidsetscrew projecting upwardly through said aligned openings, said alignedopenings being larger than said setscrew received therein and havingtheir axes inclined rearwardly of the vertical so as to permit saidclamping beam to rock forwardly and position its beveled edge in exactalignment with the forward edge of the bedplate when said cam mechanismis tightened and also to permit the beam to slide rearwardly when saidmetal is being bent at least a distance equal to the gauge of saidmetal, whereby a sharp bend is formed in said metal.

3. A sheet metal bending brake comprising a bedplate provided at itsends with holes, a clamping beam having a beveled front edge andopenings aligned with said bedplate holes, a spacing member disposedbetween the rear portions of said plate and beam, a bending beampivotally secured to said bedplate, clamping beam lifting means forraising said beveled front edge clear of said plate to permit theinsertion of metal therebetween, and cam mechanism received in saidaligned holes and openings, said mechanism including a setscrew securedin said bedplate hole, a cam associated with said setscrew, a pair ofupper and lower cam discs, said upper disc bearing against said cam andhaving a lower convex face and said lower disc having an upper concaveface receiving said convex face of the upper disc, and a cam platedisposed between said lower disc and clamping beam, said discs and camplate each having an opening aligned with each of said clamping beamopenings and said setscrew projecting upwardly through said alignedopenings, said aligned openings being larger than said setscrew receivedtherein and having their axes inclined rearwardly of the vertical so asto permit said clamping beam to rock forwardly and position its bevelededge in exact alignment with the forward edge of the bedplate when saidcam mechanism is tightened and also to permit the beam to sliderearwardly against the forward pressure of said cam mechanism when saidmetal is being bent at least a distance equal to the gauge of saidmetal.

ROBERT L. WEBB.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 713,062 Cobb Nov. 11, 1902879,415 Rude Feb. 18, 1908 942,440 Danforth Dec. 7, 1909 1,097,874Phillipi May 26, 1914 1,721,698 Krueger July 23, 1929 FOREIGN PATENTSNumber Country Date 15,284 Great Britain Dec. 12, 1885 78,623 SwedenOct. 17, 1933

